The broad goal of this project is to understand the steps involved in the hormonal control of steroidogenesis. This includes the metabolic events that follow stimulation of trophic hormone receptors in the Leydig cells, luteal cell and adrenal fasciculata cells by gonadotropins and ACTH. Studies were focused on the interaction of hormones with their receptors, and on analysis of coupling mechanism between receptor occupancy and androgen, progesterone or corticosterone synthesis. The major topics examined were (1) the relationship of receptor occupancy to cyclic AMP and protein kinase activation during acute dose-related increases in steroid production and trophic actions of gonadotropin and ACTH; (2) characterization of cyclic AMP dependent protein kinases from steroidogenic tissues; (3) the sequence of events which leads to stimulation or inhibition of enzymes of the steroidogenic cells.